In a variety of fields, workpieces must be heated to accomplish a variety of processes. Typically, after heating the workpieces, the workpieces may be cooled. Some processes do not include heating a workpiece, rather, the workpiece may be at ambient temperatures and require cooling. To hasten the cooling of the workpieces, whether heated or not, they may be subjected to additional processes that can include contacting the workpieces with one or more solids and/or fluids.
An example of a process where a workpiece is heated for processing and cooled occurs in the field of semiconductor device manufacture. Often, semiconductor substrates, such as silicon wafers, may be subjected to heat to accomplish certain process steps. The wafers may then be cooled. Typically, the cooling is a passive process where the heat is simply transferred by convection and radiation from the substrate into the surrounding atmosphere. The cooling may also be actively assisted.
FIG. 1 illustrates relationships between heat transfer and wafer temperature. In particular, FIG. 1 illustrates a relationship between radiative heat transfer Q.sub.rad and wafer temperature and a relationship between convective heat transfer Q.sub.conv and wafer temperature. As illustrated in FIG. 1, convective heat transfer is constant with wafer temperature. On the other hand, radiative heat transfer decreases as temperature of the wafer decreases. This drop off in radiative heat transfer introduces problems when trying to cool wafers since cool down rates in typical systems are about 50.degree. C. per second at about 1100.degree. C. to about 40.degree. C. per second at about 1000.degree. C. but only about 15.degree. C. at about 700.degree. C.